/**
 * Copyright (c) 2005-2010 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: HibernateDao.java 1205 2010-09-09 15:12:17Z calvinxiu $
 */
package cn.newtouch.util.hibernate;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.CriteriaSpecification;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Disjunction;
import org.hibernate.criterion.MatchMode;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projection;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import org.hibernate.impl.CriteriaImpl;
import org.hibernate.transform.ResultTransformer;
import org.springframework.util.Assert;

import cn.newtouch.util.ReflectionUtils;
import cn.newtouch.util.hibernate.PropertyFilter.MatchType;

/**
 * 封装SpringSide扩展功能的Hibernat DAO泛型基类.
 * 
 * 扩展功能包括分页查询,按属性过滤条件列表查询. 可在Service层直接使用,也可以扩展泛型DAO子类使用,见两个构造函数的注释.
 * 
 * @param <T>
 *            DAO操作的对象类型
 * @param <PK>
 *            主键类型
 * 
 * @author calvin
 */
public class HibernateDao<T, PK extends Serializable> extends
        SimpleHibernateDao<T, PK>
{
    /**
     * 用于Dao层子类的构造函数. 通过子类的泛型定义取得对象类型Class. eg. public class UserDao extends
     * HibernateDao<User, Long>{ }
     */
    public HibernateDao()
    {
        super();
    }

    /**
     * 用于省略Dao层, Service层直接使用通用HibernateDao的构造函数. 在构造函数中定义对象类型Class. eg.
     * HibernateDao<User, Long> userDao = new HibernateDao<User,
     * Long>(sessionFactory, User.class);
     */
    public HibernateDao(final SessionFactory sessionFactory,
            final Class<T> entityClass)
    {
        super(sessionFactory, entityClass);
    }

    // -- 分页查询函数 --//

    /**
     * 分页获取全部对象.
     */
    public Page<T> getAll(final Page<T> page)
    {
        return findPage(page);
    }

    /**
     * 按HQL分页查询.
     * 
     * @param page
     *            分页参数. 注意不支持其中的orderBy参数.
     * @param hql
     *            hql语句.
     * @param values
     *            数量可变的查询参数,按顺序绑定.
     * 
     * @return 分页查询结果, 附带结果列表及所有查询输入参数.
     */
    @SuppressWarnings("unchecked")
    public Page<T> findPage(final Page<T> page, final String hql,
            final Object... values)
    {
        Assert.notNull(page, "page不能为空");

        Query q = createQuery(hql, values);

        if (page.isAutoCount())
        {
            long totalCount = countHqlResult(hql, values);
            page.setTotalCount(totalCount);
        }

        setPageParameterToQuery(q, page);

        List result = q.list();
        page.setResult(result);
        return page;
    }

    /**
     * 按HQL分页查询.
     * 
     * @param page
     *            分页参数. 注意不支持其中的orderBy参数.
     * @param hql
     *            hql语句.
     * @param values
     *            命名参数,按名称绑定.
     * 
     * @return 分页查询结果, 附带结果列表及所有查询输入参数.
     */
    @SuppressWarnings("unchecked")
    public Page<T> findPage(final Page<T> page, final String hql,
            final Map<String, ?> values)
    {
        Assert.notNull(page, "page不能为空");

        Query q = createQuery(hql, values, page);

        if (page.isAutoCount())
        {
            long totalCount = countHqlResult(hql, values);
            page.setTotalCount(totalCount);
        }

        setPageParameterToQuery(q, page);

        List result = q.list();
        page.setResult(result);
        return page;
    }

    /**
     * 按Criteria分页查询.
     * 
     * @param page
     *            分页参数.
     * @param criterions
     *            数量可变的Criterion.
     * 
     * @return 分页查询结果.附带结果列表及所有查询输入参数.
     */
    @SuppressWarnings("unchecked")
    public Page<T> findPage(final Page<T> page, final Criterion... criterions)
    {
        Assert.notNull(page, "page不能为空");

        Criteria c = createCriteria(criterions);

        if (page.isAutoCount())
        {
            long totalCount = countCriteriaResult(c);
            page.setTotalCount(totalCount);
        }

        setPageParameterToCriteria(c, page);

        List result = c.list();
        page.setResult(result);
        return page;
    }

    /**
     * 设置分页参数到Query对象,辅助函数.
     */
    protected Query setPageParameterToQuery(final Query q, final Page<T> page)
    {

        Assert
                .isTrue(page.getPageSize() > 0,
                        "Page Size must larger than zero");

        // hibernate的firstResult的序号从0开始
        q.setFirstResult(page.getFirst() - 1);
        q.setMaxResults(page.getPageSize());
        return q;
    }

    /**
     * 设置分页参数到Criteria对象,辅助函数.
     */
    protected Criteria setPageParameterToCriteria(final Criteria c,
            final Page<T> page)
    {

        Assert
                .isTrue(page.getPageSize() > 0,
                        "Page Size must larger than zero");

        // hibernate的firstResult的序号从0开始
        c.setFirstResult(page.getFirst() - 1);
        c.setMaxResults(page.getPageSize());

        if (page.isOrderBySetted())
        {
            String[] orderByArray = StringUtils.split(page.getOrderBy(), ',');
            String[] orderArray = StringUtils.split(page.getOrder(), ',');

            Assert.isTrue(orderByArray.length == orderArray.length,
                    "分页多重排序参数中,排序字段与排序方向的个数不相等");

            for (int i = 0; i < orderByArray.length; i++)
            {
                if (Page.ASC.equals(orderArray[i]))
                {
                    c.addOrder(Order.asc(orderByArray[i]));
                }
                else
                {
                    c.addOrder(Order.desc(orderByArray[i]));
                }
            }
        }
        return c;
    }

    /**
     * 执行count查询获得本次Hql查询所能获得的对象总数.
     * 
     * 本函数只能自动处理简单的hql语句,复杂的hql查询请另行编写count语句查询.
     */
    protected long countHqlResult(final String hql, final Object... values)
    {
        String countHql = prepareCountHql(hql);

        try
        {
            Long count = findUnique(countHql, values);
            return count;
        }
        catch (Exception e)
        {
            throw new RuntimeException("hql can't be auto count, hql is:"
                    + countHql, e);
        }
    }

    /**
     * 执行count查询获得本次Hql查询所能获得的对象总数.
     * 
     * 本函数只能自动处理简单的hql语句,复杂的hql查询请另行编写count语句查询.
     */
    protected long countHqlResult(final String hql, final Map<String, ?> values)
    {
        String countHql = prepareCountHql(hql);

        try
        {
            Long count = findUnique(countHql, values);
            return count;
        }
        catch (Exception e)
        {
            throw new RuntimeException("hql can't be auto count, hql is:"
                    + countHql, e);
        }
    }

    private String prepareCountHql(String orgHql)
    {
        String fromHql = orgHql;
        // select子句与order by子句会影响count查询,进行简单的排除.
        fromHql = "from " + StringUtils.substringAfter(fromHql, "from");
        fromHql = StringUtils.substringBefore(fromHql, "order by");

        String countHql = "select count(*) " + fromHql;
        return countHql;
    }

    /**
     * 执行count查询获得本次Criteria查询所能获得的对象总数.
     */
    @SuppressWarnings("unchecked")
    protected long countCriteriaResult(final Criteria c)
    {
        CriteriaImpl impl = (CriteriaImpl) c;

        // 先把Projection、ResultTransformer、OrderBy取出来,清空三者后再执行Count操作
        Projection projection = impl.getProjection();
        ResultTransformer transformer = impl.getResultTransformer();

        List<CriteriaImpl.OrderEntry> orderEntries = null;
        try
        {
            orderEntries = (List) ReflectionUtils.getFieldValue(impl,
                    "orderEntries");
            ReflectionUtils
                    .setFieldValue(impl, "orderEntries", new ArrayList());
        }
        catch (Exception e)
        {
            logger.error("不可能抛出的异常:{}", e.getMessage());
        }

        // 执行Count查询
        Long totalCountObject = (Long) c.setProjection(Projections.rowCount())
                .uniqueResult();
        long totalCount = (totalCountObject != null) ? totalCountObject : 0;

        // 将之前的Projection,ResultTransformer和OrderBy条件重新设回去
        c.setProjection(projection);

        if (projection == null)
        {
            c.setResultTransformer(CriteriaSpecification.ROOT_ENTITY);
        }
        if (transformer != null)
        {
            c.setResultTransformer(transformer);
        }
        try
        {
            ReflectionUtils.setFieldValue(impl, "orderEntries", orderEntries);
        }
        catch (Exception e)
        {
            logger.error("不可能抛出的异常:{}", e.getMessage());
        }

        return totalCount;
    }

    // -- 属性过滤条件(PropertyFilter)查询函数 --//

    /**
     * 按属性查找对象列表,支持多种匹配方式.
     * 
     * @param matchType
     *            匹配方式,目前支持的取值见PropertyFilter的MatcheType enum.
     */
    public List<T> findBy(final String propertyName, final Object value,
            final MatchType matchType)
    {
        Criterion criterion = buildCriterion(propertyName, value, matchType);
        return find(criterion);
    }

    /**
     * 按属性过滤条件列表查找对象列表.
     */
    public List<T> find(List<PropertyFilter> filters)
    {
        Criterion[] criterions = buildCriterionByPropertyFilter(filters);
        return find(criterions);
    }

    /**
     * 按属性过滤条件列表分页查找对象.
     */
    public Page<T> findPage(final Page<T> page,
            final List<PropertyFilter> filters)
    {
        Criterion[] criterions = buildCriterionByPropertyFilter(filters);
        return findPage(page, criterions);
    }

    /**
     * 按属性条件参数创建Criterion,辅助函数.
     */
    protected Criterion buildCriterion(final String propertyName,
            final Object propertyValue, final MatchType matchType)
    {
        Assert.hasText(propertyName, "propertyName不能为空");
        Criterion criterion = null;
        // 根据MatchType构造criterion
        switch (matchType)
        {
        case EQ:
            criterion = Restrictions.eq(propertyName, propertyValue);
            break;
        case LIKE:
            criterion = Restrictions.like(propertyName, (String) propertyValue,
                    MatchMode.ANYWHERE);
            break;

        case LE:
            criterion = Restrictions.le(propertyName, propertyValue);
            break;
        case LT:
            criterion = Restrictions.lt(propertyName, propertyValue);
            break;
        case GE:
            criterion = Restrictions.ge(propertyName, propertyValue);
            break;
        case GT:
            criterion = Restrictions.gt(propertyName, propertyValue);
        }
        return criterion;
    }

    /**
     * 按属性条件列表创建Criterion数组,辅助函数.
     */
    protected Criterion[] buildCriterionByPropertyFilter(
            final List<PropertyFilter> filters)
    {
        List<Criterion> criterionList = new ArrayList<Criterion>();
        for (PropertyFilter filter : filters)
        {
            if (!filter.hasMultiProperties())
            { // 只有一个属性需要比较的情况.
                Criterion criterion = buildCriterion(filter.getPropertyName(),
                        filter.getMatchValue(), filter.getMatchType());
                criterionList.add(criterion);
            }
            else
            {// 包含多个属性需要比较的情况,进行or处理.
                Disjunction disjunction = Restrictions.disjunction();
                for (String param : filter.getPropertyNames())
                {
                    Criterion criterion = buildCriterion(param, filter
                            .getMatchValue(), filter.getMatchType());
                    disjunction.add(criterion);
                }
                criterionList.add(disjunction);
            }
        }
        return criterionList.toArray(new Criterion[criterionList.size()]);
    }
}
